The present invention is directed to a coupling arrangement with a first clamping ring, a second clamping ring, as well as clamping bodies, which are placed radially between the clamping rings, which are fitted inside each other, and concentrically about an axis of rotation.
This kind of coupling device is arranged between two rotating machine parts with differing relative RPMs, and which move in the same or opposed directions about an axis of rotation in a drive train, for example in an automobile transmission, or belt drive system. Power can be transferred between the machine parts through the coupling arrangement. These kinds of coupling arrangements are self-engaging or engagable free-wheels and clamp-type couplings. The difference between coupling arrangements that work one -way and those that work both ways should be noted. By means of coupling arrangements that work one way, a rotatable connection in a single direction of rotation about an axis of rotation may be made between two machine parts. Coupling arrangements that work both ways are able to make a rotatable connection between two machine parts about an axis of rotation in either a clockwise or counterclockwise direction. Each clamping ring is permanently rotatably fixed to one of the machine parts, or is able to be rotatably fixed to a machine part. The machine parts are usually at least partially positioned inside one another, radially and concentrically; The clamping rings are placed radially between the machine parts and the clamping bodies are located between them. At least one of the clamping rings has a bearing surface facing one of the clamping bodies with at least one projection situated radially in the area of displacement of at least one of the clamping bodies. The projections are arranged in one-sided or two-sided ramplike fashion circumferentially or on the side tangentially facing the clamping bodies. Speed (RPM) differentials and speed adaptations or rotating movements between the clamping rings force the clamps up against the projections, so that the clamping bodies climb up or clamp onto the ramp. The clamping bodies are then clamped between the clamping rings. A disengagable connection in the direction of rotation is thereby created between the machine parts.
The engagable coupling arrangements that make up this technology may furthermore have an actuating element. The actuating element brings about the difference in RPM or speed adaptation between the clamping rings by restricting, holding in place, or stopping the movement of one clamping ring relative to the other. These coupling arrangements are used for example in differentials and transfer cases. For example, four wheel drive may be engaged by means of this coupling arrangement. An inner clamping ring is placed on a shaft. An outer clamping ring surrounds the inner one. Clamping bodies are enclosed radially by the clamping rings. The outer clamping ring has ramplike, radial projections that protrude between the clamping bodies. Furthermore, the outer clamping ring is interrupted by a continuous groove in the circumferential direction. The clamping rings may be rotated relative to each other at an angle, and about the axis of rotation of a shaft via an actuating element. The actuating element is fitted to the inner clamping ring. The actuating element is positioned to come into contact with the outer clamping ring. On the outer clamping ring there is an outer machine part that may be turned to the outer clamping ring, for example a gear wheel. The outer machine part is separated from the outer clamping ring in such a way that a relative movement between the outer machine part and the outer clamping ring around the axis of rotation is possible while the clamping bodies are free from the ramp-like projections. A rotating movement of the shaft swivels the actuating element. The actuating element in turn acts upon the outer clamping ring in such a way that mechanical linkage is established between the clamping bodies and the ramp-shaped projections. Forces acting on the projections force the grooved outer clamping ring to spring back elastically. The forces change the outside diameter of the outer clamping ring, which comes into contact with the outer machine part in such a way that power may be applied between the machine parts through the coupling arrangement. The grooved clamping rings are knows as “slipper rings” in the trade.
The manufacture of the clamping rings for the coupling arrangement, especially the bearing surfaces with the ramp-like projections, is expensive, especially due to the machine finishing and cleaning of the bearing surfaces. The mounting of the individual parts of the coupling is relatively costly and time-consuming. Incorrect mounting and loss of parts is entirely possible. The storage and transport costs of the individual parts until their assembly by the manufacturer, i.e. a manufacturer of transmissions, are high.